A group from the University of California is working with Cook Islands marine biologist and chairperson for the environmental NGO, Kōrero o te `Ōrau, Dr Teina Rongo, to discover how corals around Rarotonga respond to high temperatures.

The university’s Assistant Professor in Evolution and Ecology, Dr Anya Brown, Dr Rachael Bay and their graduate students, Deva Holliman, Kenzie Pollard and Katie Erickson, are working with Dr Rongo, Siana Whatarau and members of Kōrero o te Ōrau.

For over a year, the team has been growing corals on tables in the Tikioki lagoon near Charlie’s, which acts like a coral nursery.

They are tracking the growth and survival of each coral in the nursery, taking small pieces from each individual coral to test for heat tolerance.

The team is also testing whether heat tolerance depends on coral diversity.

Underwater coral tables to help research what happens to the corals when sea temperatures rise. LOUISA CASTLEDINE/25020516

Dr Brown explains: “If it gets too hot, some corals bleach. They expel the tiny algae in their tissues and look bright white.”

“The tiny algae in coral tissues are responsible for converting light energy into food for the coral and without it, the coral are in danger of starving.

“If this happens on a large scale, which is happening more frequently due to climate change, then corals and all the fish, snails, and clams that rely on them are in danger of being lost.”

Dr Brown said they hope to better understand the variation in coral heat tolerance that exists in Rarotonga, lay a foundation for finding corals that are resilient to warming waters from climate change, and to inform restoration of corals in the Cook Islands and elsewhere.

Members of the community may see the team snorkelling around the shallow lagoon in Titikaveka or working with youths from Kōrero o te Ōrau.

“We have a lab set up for on-land experiments, and we are happy to share this with any students keen on coral research,” Dr Brown said.

Contact Jackie Rongo at 73560 to organise a session with these graduate students who will be on the island until early March.

The work carried out by Dr Brown, who is also a National Geographic Explorer, is funded by the National Geographic Society as part of the Perpetual Planet Ocean Expeditions programme.